Question

Estimate 78 x 437 using a general rule.

Answer 1

78×437

= 34,086

Hence 34086 is the answer

Answer 2

Answer:

For example, let us estimate the following sums:

(i) 47 + 32

We need to round the number to the nearest 10.

47 → 50

32 → 30

50 + 30 = 80

(ii) 25 + 34

Surds have infinite non-recurring decimals. Examples are √2, √5, ∛17 which are square roots or cube roots or nth root of any positive integer. For example, each of the quantities √3, ∛7, ∜19, (16)^25 etc. is a surd.